Testing equipment for automatic telephone systems



Feb. 12, 1952 gw s TESTING EQUIPMENT FOR AUTOMATIC TELEPHONE SYSTEMS 4 Sheets-Sheet 1 Filed Oct. 25, 1948 CALLED suBscPuBERs STATION CALLING SUBSCRIBERS FIG. I.

FINAL STATION 24 LINE 33 s c R )zsQN I65 2G5 3G8 468 E 5 I. F" "QT u g: 3 25 v 4 TELEPHONE EXCHANGE 3 130 T 32 REGISTER L 23 -20 n2 lzo r\..';:: 6-.

INVENTOR F. LEWIS ATTORNEY E. F. LEWIS Feb. 12, 1952 TESTING EQUIPMENT FOR AUTOMATIC TELEPHONE SYSTEMS Filed Oct. 23, 1948 4 Sheets-Shet 2 NmvE INVENTOR E. F. LEWIS BY Z i;

ATTORNEY Feb. 12, 1952 E. F. LEWIS 2,585,023

TESTING EQUIPMENT FOR AUTOMATIC TELEPHONE SYSTEMS Filed Oct. 23, 1948 4 sheets sheez 3 TEN THOUSANDS mou AND NUMBER SWITCHES UPPER DECK PA RT Y SW COUNTING SWITCH 43 79 TO TERMINALS OF STEERlNG SWITCH 5O '83 az'NORMAL ATTORNEY Feb. 12, 1952 F, F, LEWIS I 2,585,023

TESTING EQUIPMENT FOR AUTOMATIC TELEPHONE SYSTEMS Filed Oct. 23, 1948 4 Sheets-Sheet 4 DIALING DEVICE DIALING DFALiNG DEVICE DIALING DIALING DIALING CONT ROL FIG. 5.

INVENTOR E. F. LEWIS ATTORNEY Patented Feb. 12, I952 TES TIE'G' EQUIPMENT FORAUTOMATIG TELElHO'NE SYSTEMS Elmer F. Lewis, Montclair, N. J assignor to'Fed- ,era'l' Telephone: and Radio Corporation, New York, Y.," a corporation of Delaware x Application'0ctob'er23, 194s, Serial'No..56,204

usually take the form of a permanent install'a-- tion whereby connections from the exchange are extended to a wire chiefs desk-who periodically performs routine tests on all the equipment;

The object of this invention i'stc-provide a simple portable set which may be used to test the ability of: an automatic telephone exchange t connect designated calling and called lines toone another; especially in a newly installed exchange prior to: cut-overt Afeature of this. invention isthata plurality of automatic dialing units, each of which l's connectibleto. a callingand called line, will -repeat-.

edly dial the desired number and control the establishment of the connection.

According to another featureof this invention, a plurality of indicator lamps are associated with the dialing units to indicate the progress of the call. v

Still another feature of the invention is that a remote control unit is provided whereby a plurality of the automatic dialing units are'controlled;

Other features of the invention will become obvious from the following detailed description taken in conjunction with the drawings, in.

which: 1 V

Fig. 1 is a schematic diagram of a. portion of an, automatic telephone exchange;

Figs. 2 and 3 when placed end-to end show circuit diagrams of an automatic dialing device;

Fig. 4 is a circuit diagram of a control unit for a plurality of dialing devices; and

Fig. 5 is a schematic diagram of a control unit and a plurality of dialing devices connected to an exchange.

According to the present invention, a portable test device having two cables: is connected in an exchange, one cable to a calling subscribers station and the other cable connected to a subscribers station that is to be called. A plurality of multi-position switches in the-test device are:

set by hand according to the digitstof .thenumher to. be dialed. The switches control an impulse sending circuit which causes; firstia line.

' 11 claims. (on. ri -1.75.21

finder to seize the calling line, and then we a register, control group selectors and a final selector to extend the calling to'the calledlin'e and ring the called station. The operationof each selector and the ringingaof the called line arevisually indicated in" thetestde'vice which, after a successful connection, disconnects itself from thelines. After a briefperi'od the number is again automatically dialed and the callingand called lines will again beinterconnected. This cycle will'continueas long as" desired.-

By way of example, one independently'.operated automatic dialing or testing device willnow be'described. I 2

doable in the testing device having wires Zil, 21, 22', 23 is connected at the exchange in" any convenient way, to four corresponding wires 24, 25, 2'6, 2'1 of a-subscribers'line which-is tobe the calling line. Fourth wire 21 is connected to' a register in the exchange that connects ground to the wire as the register advances in the wellltno'wn manner. U a w Another cable has three wires 30,31, 32:-(Fig. 3-): which are conveniently connected at" the exchange tocorresponding: wires 33, 3'4, 35 of'a subscribersfline that is tube the called; line The connections. between the: wires ofthe test-- ing device and those of the calling and called linesmay be made either. manually .or. when. a plurality'ofi test-units are employed, by means'of step-by-st'ep: switches: (not shown). Adigit -switch 36 is set to the number: of-digits to be dialed; Number switches- 31, .3 8 ,"39; ee, 4-2 (Figs 39 are respectively" set inaccordance with the units,. tens, hundreds, thousands, ten

thousands and hundred thousandsdigits of the calledrnumber'. Ifa'the called'station-is on:a party line, party switch. 43-.i's setiirr accordance with the party line. designation. Otherwise.- the switch-1431s. left in 01f position; If thelcalled number is; for: instance 1'234'56J, digit switch'tii isplaced on 6, partyswitch; 43 on: 5; units switch 3'! on 6, tens switchilfl" on:.5','. hundreds. switch- 39 on 4-,. thousands'switcn. .40 on 3;:t'en thousands 4 1 on. 2.; andihundredi thousands" switch- Start'key Mi (Fig. 2) isthrown-to' the right, to local: position", and receiving key ii-(Fig;- 3 is thrown 'down tolocal position.- A suitable power switch (not shown) is turned on: whereupon -relays-r 4'6; 451: 811(1'481 are energized; it is energized from battery over its winding to ground at wiper 492 of. steering or marker switch 501'. Switch 513, depending onz-theisetting of digit switch 3'6 selects-the digit t'o be .dial'edand controls. the dial-- ing by advancing one step after each digit to switch control from one number switch to the next successive one until all the digits of the called number have been dialed. When switch 50 is in normal position Wiper 49 rests on terminal 5| and a white lamp 52 is lighted indicating that the, device is in normal condition and ready to, begin operation. Relay 4] is energized over a back contact of relay 53, and 48 is energized over a front contact of 41.

Relay 54 now operates over front contact of 46, key 44 to ground at a backcontact of ground control relay 55. Relay 54 looks over a right hand front contact to the sameground and the I circuit comprising wires 20, 2|, .which, as pre-,

51 back, 59 front, '62 front, back contact of relay 61, back contact of 68, winding relay 64, to battery through the interrupter springs of magnet 69 of counting switch 18. One of the sets of terminals of switch is multipled to all the number switches and the upper deck of the party switch.

Relay 1| operates in, parallel with relay 62 through another back contact of relay 61 and shorts out talk coil 56 over a front contact because dialing cannot take place with the talk "coil'in the dialing circuit. The short is main- 'tained during dialing to prevent listening or talk- ,ing over a jack 12.

viously explained, have been connected to-the calling line, is closed over left hand front contact relay 54, back contact of dialing" relay 64,"

right hand front contact of 54, talk coil 56. Relay 51 is energized over a left hand front contact of 54. Y M

The closing, over the contacts of relay 54, of the circuit comprisingwires 28, 24 and wires 2|, 25 operates the line finder in the usual manner to seize the calling line and the; register in the exchange is attached to the line finder and connects ground to wire 23, all in the well known manner. Relay 53 is thereby energized and ground is locked to wire 22 over left hand front contact of 53. A green lamp 58 is lit overright hand front contact of 53 to indicate the beginning of dialing.

Energization of relay 53 removes ground from relay 41 which releases and in turn deenergizes relay 48. Relay 48'has a condenser of suitable value placed across its winding and therefore delays in releasing for a period sufficient to permit the register in the, exchange to advance to a waiting position, whereupon relay 48 releases. Relay 59 is then energized over the back contacts of relays 41 and 48 and locks over its ownleft hand front contact to ground at relay 55 over the left hand front contact of relay 51. W

The operation of relay 59 energizes relay 60 over the interrupter springs of magnet '6| .of,

steering switch .58, back contact relay 62, right hand front contact 59, left hand front contact 51, ground right hand back. contact relay 55. Magnet 6| is energized over the front contact of;

relay 60 and causes switch 50 to take onestep This will operate the interrupter springs of the magnet whereupon relay 66 is released. -When 60 deenergizes it opens the circuit of magnet 6| which, in turn, releases and reenergizes relay 68.

This cycle of operation continues and steering As switch 58 takes its first step wiper 49 moves off terminal 5| and relay 46 deenergizes, thereby opening the operating circuit of relay 54.

However, '54 remains locked up over a right hand front contact. Relay '65 is now energized over the back contact of relay 46. The front contact of relay 65 connects wire 23 to the relay 66 which. controls metering of the call in the well known.

manner.

When relay '62 becomes energized the start ground at relay 55 is applied to wiper 63 of switch. 50. The ground at relay 55 is connected also via @With dialing relay 64 energized, ground from relay 55 over right hand front contact of 64 energizes relay 13. Relay 13, over a left hand front contact, connects this ground to magnet 69. A timing circuit comprising a condenser and an adjustable resistor are across the winding of magnet 69. This timing circuit plus a series resistor 16 in the operating circuit of magnet 69 insures that it will be slow operating. When magnet 69 operates its opens its own interrupter springs thereby deenergizing relay 64 which in turn deenergizes relay 13 and removes ground from magnet 69. Relay 13 is slow in releasing and therefore remains energized during the pulsing cycle of relay 64 and releases only after each digit has been dialed. The previous operation of steering switch '58 moved its wiper 11 onto terminal 18, whereby ground is placed on the arm of hundred thousands switch 42 and if switch 42 is set to number 5 ground is placed on the fifth terminal in the arc of wiper 19 of counting Switch 10 will continue to advance step by step until wiper 19 encounters the ground from hundred thousands switch 42. This ground energizes relay 68 thereby opening the operating circuit of dialing relay 64. Relay 68 looks over its front contact to ground at relay 55 over wiper 82. Relay 13, which was energized during the operation of dialing relay 64 now releases and places ground over its back contact on wiper 83, any terminal engaged by wiper 83, winding of relay 84 to battery through the interrupter springs of magnet I59. When 84 operates, ground from its front contact is placed on the winding of magnet 69 which operates and, in turn, opens the circuit of relay 84. In this manner switch 10 is stepped around until it returns to its normal position in which ground is removed from relay 84. Relay 68, While switch 10 is being stepped around to normal, operates to remove the timing circuit from magnet 68 so that switch 10 may be .rapidly restored to normal. When the switch reaches normal the locking path of relay 68 through wiper 82 is opened and relay 68 releases thereby transferring the operating ground to dialing relay 64 and restoring the timing, circuit. Relay 64 becomes Y energized after slow acting relay 13 has been operated during the relay 13 deenergizes, as well as during th return of switch 10 to normal, steering switch 50 takes.

onestep to extend ground from wiper 19 to the next successive number switch, the ten thousands digit switch 4i. Relay 64 in a magnet 69 again steps switch 7'0 until wiper l5 encounters a ground placed on its terminal by ten thousands number switch 4|. Thereafter, relayfiB operates to restore the switch It as above described.

These operations are repeated for each number switch. Party switch 43 is the last number switch to operate and has a make contact on its lower deck in off position that shorts the seventh and eighth terminals of wiper 53. When wiper 63 reaches the seventh terminal, "ground is placed on the Winding of relay 6'! which opens the operating circuit of dialing relay 54 and stops dialing. If it is desired to dial a party digit the party switch will beset on the desired number and this digit must be transmitted before wiper 63 of switch 50 reaches the eighth terminal and causes the operation of relay 51.

Lamps 85-53 are connected to one of the sets of terminals of switch 55 and light as each digit is dialed to provide visual indication of the progress of the dialing.

When the dialing is completed, the final selector in the exchange places ground on wire 35 of the called line, in the well known manner. This wire is connected to wire 32 in the testing device and relay 94 is energized and a red lamp 95 lights.

In the usual manner ringing current is applied to the called line and wires 30 and iii to energize relay 96 which has a ZMFD condenser 97in its circuit. Relay 98 is now energized over front contact of 95 to ground on a back contact of 55.

Relay 58 locks itself over a left front contact to the same ground and a white lamp 59 lights. By means of another front contact, relay 93 places coil Hi5 across the incoming line, thereby tripping the ringing current. A jack i! is provided across the incoming line to permit listening and talking.

In a well known manner the first group selector in the exchange connected to the circuit under test will place battery on wire 23 whereby metering will take place via the front contact of relay 65 and the message register.

Ground control relay 55 is energized over a left hand front contact of relay 98 and key 45. Relay 55 is slow-operating permitting sumcient time for the first group selector in the exchange to advance for metering. Relay 55 remains operated for a short period thereby removin locking ground of relay 54 and the calling line is released. Energization of 55 also opens the locking circuit of relay 98 thereby releasing the called line. -Deenergization of relay 54 permits relay to release, thereby deenergizing relay Bland 59. When relay 5! is deenergized a ground from a left hand back contact is placed on wiper H32 of switch 50. This ground is extended through wiper 33 of switch 10, through the interrupter contesting devices under the supervision of a control device will now be described, referring particularly to Figs. 4 and 5 in which the circuit of such a control devicc is shown. I

Each of a plurality of the automatic devices is connected in the exchange to the lines to :be tested. The dial, number and party switches in each device are set to the called numbers. Start keys 54 in each device are thrown to the left or remote operating'position and receive keys thrown up. Terminals I of the devices are multipled to terminal I07 of the control unit. Terminals I08 of the devices are multipled to terminal I99 of the control unit. Terminals IHI of the dialing devices are multipled to terminal I ll of the control device. Terminal -I I2 of the control device connects to terminal I13 of one of the dialing devices. A terminal H4 in this dialing device extends this connection to the next device which extends it to the following one, thereby connecting the devices in series. This connection is continued through all the devices to ground at the last one.

Operation of master start key H5 "(Fig 3) places ground on all the starting circuits of the individual devices, to energize relay 54 in each device, terminal Hi9, terminal H18, left hand position key 44, left hand front contact relay 46 and battery at relay 54. Indicator lamp H6 in the control unitlights to show that operation of the unit has commenced. Relay 54 is locked over a right hand front contact to ground at left hand back contact of ground control relay H1 in the control unit, right hand front contact 54, key 44, terminal Hi5, terminal 101, and ground left hand back contact Ill. Indicator lamps i I8, H9 in the control unit light to show that ground is connected to the calling and called lines.

Each device as above described, Will now proceed to dial the number of its called line. As a device completes it call its relay 98 will lock to ground, left hand front contact relay 98, key 45 in raised position, terminal H0, terminal Hi to ground at right hand back contact relay I H.

l With key I25 in normalposition as each device completes its call lamp I21 will light.

,A link circuit that connects all the devices in series is closed over terminals H3 and H4, over a right hand front contact relay 98. If each device is successful in putting through its call and all the relays 98 operate, the link circuit will be closed over terminal H2 and key I25, whereupon indicator lamp 12'] lights. If key l20 is in the down position lamp |2l will not light and ground from the last device over the series connection will be connected to battery at relay H1. A suitable timing circuit is placed across the winding of relay I I! to make it slow operating so that the first group selectors in the exchange may cause metering in the well known manner. When relay H1 operates, lamps H8 and H9 are extinguished and ground 'isrem'ovedfrom all relays 54 in the dialing devices and all the calling lines are released. Operation of relays 55 opens the circuits of relays and-all the called lines are released. Lamp I22 is thereupon operated over left hand front contact of relay 1 Hand indicates the termination of all the calls. Message register relay I23 for the group of devices will thereupon be energized; The dcenergizat-ion of relays 98 opens the series connection between the individual devices and relays H1 is slowly deenergized.

If oneof the devices has been unable to complete its call for any reason, the series connec-'- tion will not be closed and dependingon the position of key 120, lamp IZl or 122 will not light. Inspection of the individual devices will reveal which one has failed to put through its connection, since its white lamp '99, that indicates whether or not ringing current has been applied to the called line, will not be lit. By placing a busy block in jack 12 of this device so as to hold the call, the power of the device may be turned ofi and its start and receive keys placed in normal position. When key 45 is in normal position the series connection may be completed around the inoperative device and the rest of the devices and the control unit will continue to operate.

Variations and other embodiments of the invention will be suggested by the foregoing to those skilled in the art. However, it is intended to limit the invention only by the scope of the appended claims.

What I claim is: 1. In a telephone exchange system, a plurality of. subscribers lines, means for establishing a connection between a calling and a called line, a testing device for operating said means to establish connections between calling and called lines comprising means for connecting the device to a line desired to be tested as a calling line, means for connecting the device to a line desired to be tested as a called line, a digit switch having contacts and an arm' cooperating therewith, said arm being movable with respect to the contacts to indicate the number of digits to be dialed, a plurality of number switche each having contacts and an arm cooperating therewith, a steering switch having terminals and wipers cooperating therewith, terminals of the steering switch connected to contacts of said digit switch and to arms of the number switches, a counting switch having terminals and wipers cooperating therewith, terminals of the counting switch connected to the contacts of the number switches, means for moving the wipers of said steering switch, means for moving the wipers of said counting switch, a dialing relay controlled by said switches whereby pulses corresponding to the number of the called line are transmitted to the exchange to operate the means for establishing the connection to the called line, relay means operable after a predetermined time for releasing the called line, and indicator lamps connected to the terminals of the steering switch for indicating the dialing of each digit.

2. In a telephone exchange system, a plurality of subscribers lines, for establishing a connection between a calling and a called line, means for ringing the called line, a testing device for operating said means to establish connections between calling and called lines comprising means for connecting the device to a line desired to be tested as a calling line, means for connecting the device to a line desired to be tested as a called line, a digit switch having contacts and an arm cooperating therewith, said arm being movable with respect to the contacts to indicate the number of digits to be dialed, a party switch having contacts and an arm cooperating therewith, a plurality of number switches each having contacts and an arm cooperating therewith, a steering switch having terminals and wipers operating therewith, terminals of the steering switch connected to contacts of said digit switch and to the arms of said party and number switches, a counting switch having terminals and wipers cooperating therewith, terminals of the counting switch connected to the contacts of all the number switchesand of the party switch, means for moving the wipers of said steering switch, means for moving the wipers of Said counting switch, a dialing relay controlled by said switches whereby pulses corresponding to the number of the called line are transmitted to the exchange to operate the means for establishing the connection to the called line and for ringing it, relay means operable to trip the ringing means after the call is completed, relay means operable after a predetermined time for releasing the called line, and an indicator lamp connected to the terminals of said steering switch whereby the dialing of each digit is indicated.

3. In a telephone exchange system, a plurality of subscribers lines, means for establishing a connection between a calling and a called line, means for ringing the called line, a testing device for operating said means to establish connections between calling and called lines comprising a first cable connectible to a line desired to be tested as a calling line, a second cable connectible to a line desired to be tested as a called line, a digit switch having contacts and an arm cooperating therewith, said arm being movable with respect to the contacts to indicate the number of digits to be dialed, a party switch having contacts and an arm cooperating therewith, a plurality of number switches each having contacts and an arm cooperating therewith, a steering switch having terminals and wipers cooperating therewith, one set of said terminals connected to contacts of said digit switch and another set to the arms of said party and number switches, a counting switch having terminals and wipers cooperating therewith, one set of the counting switch terminals being multipled to the contacts of all the number switches and of the party switch, means for moving the wipers of said steering switch, means for moving the wipers of said counting switch, a dialing relay controlled by said switches whereby pulses corresponding to the number of the called line are transmitted to the exchange to operate the means for establishing the connection to the called line and for ringing it, relay means connected over said second cable to the called line operable to trip the ringing means after the call is completed, an indicator lamp operable by said last-mentioned relay means for indicating the ringing of the called line, relay means operable after a predetermined time for releasing the called line, and an indicator lamp connected to each terminal of one of the sets of terminals of said steering switch whereby the dialing of each digit is indicated.

4. A telephone exchange system having a plurality of subscribers lines, means for establishing connections between calling and called lines, a plurality of automatic dialing devices, for operating said means to establish connections between calling and called lines, each of said dialing devices comprising means for connecting it to a line desired to be a calling line and to a line desired to be a called line, a plurality of multi-position switches movable into positions corresponding to the number of digits to be dialed, means controlled by said switches for transmitting to the exchange pulses in accordance with the digit settings of said switches to operate the means for establishing the connections between calling and called lines, a control means for said devices,

9 ing that at least one of the devices has not completed its call.

7. The device according to claim 4, and first indicating means in said control means for indicating completion of a call by each device, and second indicating means in the control means for indicating that at least one of the devices has not completed its call.

8. A telephone exchange system having a plurality of subscribers lines, means for establishing connections between calling and called lines, a plurality of automatic dialing devices for operating said means to establish connections between calling and called lines, each of said dialing devices comprising means for connecting it to a line desired to be a calling line and to a line desired to be a called line, a plurality of multi-position switches movable into positions corresponding to the number of digits to be dialed, means controlled by said switches for transmitting to the exchange pulses in accordance with the digit settings of said switches to operate the means for establishing the connections between calling and called lines, a control unit; multiple connections from the control unit to each dialing device, a series connection from the control unit through each dialing device closed after all the dialing devices have completed their calls, indicating means in the control unit for indicating that at least one of the devices has not completed its call, and indicating means for indicating closing of said series connection.

9. The device according to claim 8, and indicating means in each dialing device for indicating its operation.

10. A telephone exchange system having a plurality of subscribers lines, means for establishing connections between calling and called lines, means for ringing the called lines, a plurality of automatic testing devices for operating said means for establishing connections between calling and called lines, a remote control unit, multiple connections from said control unit to each testing device, a link circuit extending from the control unit through each testing unit connecting said plurality of testing devices in series, said link circuit being closed after all the testing units have completed their calls, indicating means in the control unit for indicating that at least one of the devices has not completed its call, and indicating means for indicating closing of said series link circuit.

11. A telephone exchange system having a plurality of subscribers lines, means for establishing connections between calling and called lines, means for ringing the called lines, a plurality Of automatic testing devices for operating said means for establishing connections between calling and called lines, a remote control unit,

10 multiple connections from said control unit to each testing device, a link circuit extending from the control unit through each testing unit connecting said plurality of testing devices in series, said circuit being closed after all the testing units have completed their calls, indicating means in the remote control unit for indicating that at least one of the devices has not completed its call, indicating means for indicating closing of said series circuit, each of said testing devices comprising, a first cable connectible to a line desired to be tested as a called line, a digit switch having contacts and an arm cooperating therewith, said arm being movable with respect to the contacts to indicate the number of digits to be dialed, a party switch having contacts and an arm cooperating therewith, a plurality of number switches each having contacts and an arm cooperating therewith, a steering switch having terminals and Wipers cooperating therewith, one set of said terminals connected to contacts of said digit switch and another set to the arms of said party and number switches, a counting switch having terminals and wipers cooperating therewith, one set of the counting switch terminals being multipled to the contacts of all the number switches and of the party switch, means for moving the wipers of said steering switch, means for moving the wipers of said counting switch, a dialing relay controlled by said switches whereby pulses corresponding to the number of the called line are transmitted to the exchange to operate the means for establishing the connection to the called line and for ringing it, relay means connected over said second cable to the called line operable to trip the ringing means after the call is completed, an indicator lamp in said testing device operable by said last-mentioned relay means for indicating the ringing of the called line, relay means operable after a predetermined time for releasing the called line, and an indicator lamp connected to each terminal of one of the sets of terminals of said steering switch whereby the dialing of each digit is indicated.

ELMER F. LEWIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,808,902 Miller June 9, 1931 2,065,894 Hovland Dec. 29, 1936 2,253,650 Richard Aug. 26, 1941 2,293,588 Cain Aug. v18, 1942 2,345,959 Blessing Apr. 4, 1944 2,358,267 Vander Els Sept. 12, 1944 

